How many solar panels do I need for heat pumps?

Air source heat pumps are an incredible investment in your home's energy efficiency, but the energy savings don't have to stop there. Powering your heat pump system with solar panels can maximize energy bill savings while decreasing your carbon footprint. But how do you size a solar system to meet your heating and cooling needs? In this article, we discuss what you need to know and discuss with your solar installer to ensure your solar system can power your heat pumps.

Air source heat pump technology has evolved to fit various heating and cooling needs –  you can now buy heat pumps designed for only one room (a single-zone system) or those that can heat and cool multiple zones throughout your house; there are also central ducted systems or ductless mini-splits! While this means that more homes can enjoy the benefits of heat pumps, it makes estimating an air source heat pump's electricity needs a bit more complicated.

The model of the heat pump and the area of the space it's expected to heat and cool aren't the only factors to consider when estimating the energy usage of air source heat pumps. The geography and insulation of your home play a crucial role in energy expenditure: a well-insulated home is better at retaining heat in the winter than one with poor-quality insulation and, therefore, won't require as much electricity to heat.

The Department of Energy (DOE) estimates that given 1,400 hours of both heating and cooling a year (2,800 hours of use total), a 36,000 BTU/h central ducted air source heat pump consumes between roughly 5,000 and 10,000 kWh annually, depending on the efficiency of the model you choose:

Average air source heat pump electricity usage

Source: Department of Energy

These consumption numbers indicate a property using air source heat pumps as their primary heating source. Units designed to heat larger spaces will likely consume more electricity, while ductless mini-splits heating and cooling either smaller homes or only a single zone should consume less. Because the energy needs of these technologies are so specific to your property, geography, the efficiency of the product, and your heating and cooling habits, the best way to get an accurate estimate for anticipated electricity consumption is to obtain a quote from a qualified contractor.

Similar to air source heat pump energy usage, many factors contribute to your property's solar potential. In addition to the region you live in, the location of your solar panels plays an important role in energy production. Everything from their tilt and the direction they face to the amount of shade impacts the production potential of a solar array.

Below are some rough estimates of the annual solar panel generation in various regions. For these estimates, we assumed 400-watt (W) solar panels, the most frequently selected panels on the EnergySage Marketplace, in the first half of 2022.

Average production per solar panel by U.S. region

Based on these estimates, you will need between two to three 400 W solar panels to generate 1,000 kWh annually. But as previously mentioned, this heavily depends on the specifics of your geography, property, and solar array design, so it's important to confirm any estimates with a professional installer.

Once you understand your heat pump's electricity needs and your home's solar potential, you can calculate how many solar panels you might need to run your air source heat pump. To roughly estimate what it will take to cover the heat pump's energy needs, simply divide your air source heat pump's estimated annual electricity consumption by the expected output of a 400-watt solar panel in your region. Using the scenario above, a central ducted air source heat pump system would require:

Once again, these numbers reflect a system that serves as the primary heating and cooling source. Other technologies, like ductless mini splits or smaller systems, require less electricity and therefore require fewer solar panels. For example, an efficient 12,000 BTU mini split system that consumes around 2,000 kWh annually would need between three and five solar panels.

Now that you know how to estimate the number of solar panels required to power an air source heat pump system, you're ready to start comparing quotes from local solar installers. What is the wattage of the solar panels they are quoting? Where will the solar panels go on the property? How efficient is the air source heat pump model you want to power with solar? It's important to think about things like this when comparing professional estimates.

It's best to consult a local installer to understand the energy needs of your air source heat pump and solar panel systems. When you receive quotes through the EnergySage Marketplace, we'll even connect you with an Energy Advisor to guide you through each quote, free of charge!